The field of art to which this invention pertains is the hydrocracking of a hydrocarbonaceous feedstock having a propensity to form 11.sup.+ ring heavy polynuclear aromatic compounds without excessively fouling the processing unit. The 11.sup.+ ring heavy polynuclear aromatic compounds are considered to be refractory in a hydrocracking process, are thereby highly resistant to conversion in a hydrocracking reaction zone and are therefore undesirable components in the feed or recycle to a hydrocracking reaction zone.